If we considered it's with their NPs like Avalon, Arthur or Artoria, but Imma choose Charlemagne because my goat

For some reason, I always think that Arthur is stronger than Artoria. This opinion of mine arose because Arthur's Excalibur is one rank higher than Artoria's. On the other hand, Artoria has Avalon, while Arthur does not, or at least we don't know if he has it.

Well, Arthur can see simply unlock the limiters Excalibur has (though it is somewhat limited from what I remember) while Artoria can't (from what I remember/understand, though I may be wrong)

As far as I know, Arthur needs to meet several conditions to break the seals. I haven't made much progress in reading the Prototype yet, so I'm just saying what I know.